High speed automated machinery has been used and can continue to be used in modern beverage bottling plants, particularly in connection with carbonated beverages. When filling containers with carbonated beverages, the method and apparatus employed involves providing a liquid beverage and carbon dioxide under pressure in a manner that counter pressure in the container facilitates filling the containers with accurately predetermined quantities of liquid beverage. Typically the machinery includes a rotating table which is fed by conveyors with empty containers and having eight, twelve or more filling stations each having a filling valve. The containers enter the rotating table from an entry conveyor and are filled while progressing around a table and turret. Usually there is a capping process also effectuated before the containers leave the turntable onto an exit conveyor.
The manner in which the containers are properly located at a filling station and sealing contact is made by engagement and disengagement with a bottle sealing rubber all form no part of the present invention and the details thereof are not expressly disclosed herein. Specifics of such matters are well known in the art as well as being readily available from prior patents referred to herein and which are incorporated by reference for that purpose. The specific embodiment of filling valve illustrated and described herein is particularly adapted for incorporation in a very well known beverage container filling machine, commonly referred to as a Crown filler. It will be apparent however that the principles embodied in the invention are also adaptable to filling valves for other brands and other types of beverage bottle filling machines.
Filling machinery which employs filling valves to which the invention relates customarily include a reservoir above the filling valves containing the liquid beverage which is to flow under the effect of gravity into the containers. The gas above the liquid is pressurized and normally provides the carbon dioxide carbonating gas to be used to charge the container. The tops of filling valves extend into the reservoir from below and provide conduits from the reservoir to the empty container. According to a long known and well known process, initially the gas valve of the filling device fills a container with a counter pressure gas before the bottle or the container is filled with liquid by opening the filling valve incorporated in the filling device.
As the liquid fills the container, gas in the container being displaced is evacuated through a tube incorporated in the filling valve upwardly into the gas and liquid reservoir. When the level of liquid in the container rises to the opening of the tube, the gas which previously could escape through the tube can no longer escape and gravity flow of the liquid ceases under the altered pressure relationship. Shortly thereafter, the liquid and gas valves are closed and customarily a snifter is operated designed to release the remaining excess pressure in the container before its release and departure from the filling device.
In the Crown filler and in other forms of filling machines, the valves are generally controlled and synchronized by mechanical cams or other mechanical or electrical means to control the above sequence where gas is admitted to the container for counter pressurizing the gas in the container after which the liquid flow valve is opened, the filling process is completed, the valves are closed and the pressure in the neck of the container is appropriately released by a snifter valve.
While the technique of liquid level flow in the container relying on pressure balance to terminate the flow and provide proper filling of the containers is theoretically sound and generally effective, small quantities of liquid will continue to pass into the container due to the relatively large cross-sectional area for liquid passage. A common technique to eliminate or suppress the after flow when pressure balance is produced (by the liquid rising to above the vent tube opening) has been to put a fine screen, preferably with capillary size openings, across the liquid flow path. With this arrangement, the small capillary openings in the screen operate in conjunction with the surface tension of the liquid to virtually prevent any further flow when the gas pressure below the screen comes equal to or nearly equal to the pressure of the liquid above the screen. In filling valves various forms of such screens have been proposed in various locations in the valve as is shown in various patents including U.S. Pat. No. 5,060,702 granted Oct. 29, 1991 to LaWarre Sr. et al., and U.S. Pat. No. 4,349,055 issued Sep. 14, 1982 to Dichiara. A problem with these types of assemblies is the position of the screen in the high pressure area may produce additional foaming, and in any case the screen undesirably restricts the liquid flow through the valve before the liquid rises to the desired fill level.